Medication in forms such as tablets, capsules, caplets, or fast-dissolving dosage forms have been typically packaged in blister packages or sheets of multiple blister pockets or compartments. A base sheet of transparent or opaque plastic, for instance polyvinyl chloride (PVC or PVC-type laminates), will frequently have a plurality of blister pockets projecting from one face thereof, for containing the unit dosages of medication.
If the units of medication to be packaged in the blister package are solid units such as tablets, capsules, or caplets, the solid units may simply be deposited into the blister pockets of the base sheet. On the other hand, if the units to be packaged are freeze-dried, fast-dissolving dosage forms (FDDF), the medication may be dosed and frozen directly within the blister pockets and then dried therein using a freeze-drying process, as explained by Gregory et al., U.S. Pat. No. 4,305,502. The freeze-drying process is well known in the art and may involve first dosing a liquid suspension into the preformed blister pockets of a base sheet. The base sheet containing the suspension is then cooled by a medium such as liquid nitrogen or carbon dioxide, thereby freezing the contents of the blister pockets. The frozen contents may then be subjected to reduced pressure to complete the freeze drying process.
Various techniques which can utilize preformed pockets (such as blister pockets) to create fast-dissolving dosage forms are described in (i) U.S. Pat. Nos. 5,120,549 and 5,215,756 (hereinafter referred to as the "Gole Process"); (ii) U.S. Pat. No. 5,298,261 (hereinafter the "Pebley Process"); and (iii) U.S. Pat. Nos. 5,039,540 and 5,079,018 (hereinafter the "Ecanow Process"), the entire teachings of which are herein incorporated by reference. Another technique is described in PCT Application No. JP 92/01631 filed Dec. 12, 1992 and published as International Publication No. WO 93/12769 (referred to as the "Yamanouchi Process"), the entire teaching of which is incorporated herein by reference. Each of the references disclose techniques to create a fast-dissolving dosage which is at least formed (in contrast to fully processed) in a pocket.
In broad terms, the Gole Process describes a dosage form using a solid-state dissolution method whereby a delivery matrix and first solvent are solidified and subjected to a second solvent at a temperature which permits the removal of the first solvent while leaving the matrix as the product.
The Pebley Process discloses a method of preparing a rapidly disintegrating tablet involving vacuum drying the unbound liquid from a matrix at a temperature above the collapse temperature (i.e., initial matrix melting point) during primary drying, thereby evaporating the free solvent through solid to liquid to gas phases (as opposed to conventional lyophilization which removes solvent directly from solid to gas).
The Ecanow Process discloses a method of preparing freeze-dried readily dissolvable formulations by combining a hydrated gel or foam together with a rigidifying agent and subsequently dehydrated with an anhydrous organic liquid desiccant at about 0.degree. C.
The Yamanouchi Process discloses intraorally disintegrating solid preparations prepared by combining the active ingredient with a sugar (such as lactose and/or mannitol) and agar. The dosage forms are then dried under decreased pressure or forced air conditions.
The pharmaceutical industry abounds with a variety of dosage forms, many of which are very similar, if not identical to each other in outward appearance. It is therefore often necessary to place an identifying logo, code, or other mark on each individual dosage form. Such mark might identify the manufacturer, the brand name, the active component strength or any other useful information regarding the dosage form. Further, several states in the United States currently require certain identifying markings to appear on individual units of medication.
Solid units of medication such as tablets, capsules or caplets have been acceptably identified by printing information directly onto the unit. Alternatively, solid units have been embossed with an identifying mark by compressing an embossment into the surface of the unit. The latter method is illustrated by or analogous to the processes disclosed by Roberts in U.S. Pat. No. 3,534,440; Weinberg in U.S. Pat. No. 2,645,852; and Tobin in U.S. Pat. No. 510,453, which disclose direct pressing techniques to emboss various articles.
While such methods are well suited to the application of an identifying mark to most solid units of medication, such methods are not well-suited for the application of identifying marks to fast-dissolving units. In particular, the application of compression techniques would cause deformation, reduced porosity and increased dispersion time, as well as possibly cracking the fast-dissolving dosage forms due to their inherent fragility, surface undulation, moisture sensitivity and chemical makeup. Similarly, the chemical make-up, moisture sensitivity, porosity and surface undulation of fast-dissolving dosage forms would cause ink to dissolve the dosage forms at the point of contact or to diffuse throughout the dosage forms leading to clarity problems.
Therefore, the need exists for improved products and methods of manufacturing relating to fast-dissolving dosage forms and embossing them without adversely affecting the structural or chemical properties thereof.